package com.demo.springcloud.lb;

import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author :chenjie
 * @date :Created 2022/11/2 23:26
 */
@Component
public class MyLB implements LoadBalancer{
    private AtomicInteger atomicInteger=new AtomicInteger(0);
    public final int getAndIncrement(){
        int current;
        int next;
        do {//自旋锁
            current =this.atomicInteger.get();
            next=current>=2147483647?0:current+1;//防止越界

        }while (!this.atomicInteger.compareAndSet(current,next));
        System.out.println("******next"+next);
        return next;
    }
    @Override
    public ServiceInstance instance(List<ServiceInstance> serviceInstances) {
        int index=getAndIncrement()%serviceInstances.size();//实际调用服务器位置=rest接口第几次请求数%服务器集群总数

        return serviceInstances.get(index);
    }

}
